Driving mechanism



June 1950 H. M. STEPHENSON 2,511,678

DRIVING MECHANISM Filed Dec. 12, 1945 Invehoor- Hugh M. StephensonHisAttor-ne bers. In this illustrated construction, a trigger member I6is pivotally mounted by a suitable pin I1 on the driven member and isformed with an engaging finger element I8 arranged in direct mechanicalengagement with a driving projecting element I9 formed on the other endof the spring 6 and spaced circumferentially' from the drivingprojection I of the spring. During normal operating conditions, thistrigger I5 forms no part of the driving mechanism and is held'out offrictional engagement with the hub I of the drivthe trigger I6 throughits finger I8 in a counter- "clockwise direction, thereby causing thetrigger ing member by a latching mechanism which includes a memberpivotally mounted by a .suitable pivot pin 2| on the driven member'plate9. This latching member 20 is formed with a step 22" on the innersurface thereof which is adapted 'to engage the end 23 of the trigger I6to hold the inner surface 24 of the trigger I6 out of en- 'gagement withthe hub I. If the torque transmitted through the frictional drivingconnection exceeds a predetermined value, slippage occurs between thedrum 5 and the spring 6, causing relative movement between the drivingand driven -'members, and an actuating element which is shown formed asa roller 25 rotatably mounted -on a suitable pin 26 secured to thedriving member drum portion 5 rotates with the driving member from aposition such as that shown in Fig. 1 into engagement with the undersurface 24 of the trigger I6, as shown in Fig. 2, thereby turning :thetrigger I6 in a clockwise direction, as seen in this figure, about itspivotal support I1. This =compresses the arcuate spring 6 out offrictional engagement with the driving member drum surface by biasingthe ends of the arcuate spring towards each other through the clockwisemove- :ment of the trigger finger I8 on the projection I9 ofthe spring,thus releasing the frictional driving ."engagement between the springand the driving member drum. In many installations, it is desir- -ablethat the driving connection should not be reestablished except by manualresetting of the driving mechanism. This is provided for in thisembodiment of my invention by providing an -angu1arly arranged camsurface 21 on the latching member 20 which is adapted to engage acomapl'ementary camming surface 28 on the end 23 'of the trigger I6 forfurther biasing the trigger lsioutwardly out of engagement with theroller 25 to a position such as that shown in Fig. 3. A .stop 29 isformed on the end of the latching .member 26 to prevent further outwardmovement -.of the trigger I6 and to hold the trigger I6 and .thelatching member 20 in the positions shown in Fig. 3. This camming actionis facilitated by the -:provision of a resilient spring biased resetdevice .including a member 30 which is suitably secured .as by a key orextension into a slot in the end Lof the latching finger pivot pin 2|and is biased in a clockwise direction around the pivot pin 2| -by acoil spring 3| arranged in compression between a spring seat 32 on thefinger 30 and the bottom of a recess 33 formed in a shoulder 34 on thedriven member hub II, thereby assisting in latching the arcuate spring 6in its compressed position out of engagement with the friction surface 4of the driving member drum portion 5. This resetting device is soconstructed that when :it is desired to reestablish the frictionalengagement between the spring 6 and the surface 4 of :the drum 5, thespring lbiased end of the reset finger 36 may be pressed inwardly,thereby rotating the finger 30 and the latching member 20 in acounterclockwise direction about the pivot I6 to move inwardly. Releaseof the reset finger 30 causes this finger and the latching member 26 toturn in-a clockwise direction under the action of the coil spring 3 I,such that the latching member 26 and the trigger I6 will again assumethe positionshown in Fig. 1. In this construction, a pair of centeringpins 35 and 36 are mounted on the driven member plate 9 and spacedslightly inwardly from the expanded position of the arcuate spring 6 forcentering the spring relative to the mechanism as the spring is drawninwardly by its compression under the action of the trigger I6.Furthermore, in order toprovide a desired adjustment in the compressionof the spring 6 and also to provide necessary adjustment for slightvariations in the dimension of the comsecuring device, such as a screw38 extends for securing the end of the member 8 in different positionsto provide for adjustment of the position of this member relative to theprojecting end portion I of the spring 6.

In Fig. 6, I have shown a modification of the trigger and stop membersshown in the other figures of this drawing in which a stop member 39 ispivotally secured by a pivot pin 46 to the driven member plate 9 and isformed with an engaging finger 4| which is adapted to provide a directmechanical engagement with the projecting end portion 1 of the spring 6.A tongue 42 is formed on the stop member 39 and extends into acomplementary groove 43 formed in the adjacent end of the trigger I6,such that a clockwise movement of the trigger I6 produces acounterclockwise movement of the stop 39, thereby providing a quickercompression of the arcuate spring 6 by a simultaneous movement of thetwo ends of the spring towards each other when the trigger I6 isactuated to its released position. The other parts of this mechanism maybe made substantially the same as those shown in the other figures ofthe drawing and operate in the same manner as explained with respect tothese other figures.

The above description has been given while considering the rotation' ofthe driving member '4 to the projecting end I8 of the trigger member -I6which is pivotally mounted on pin H to the driven member and positionedby the latch 20 at step 22. It is also apparent that the functioning ofthe device is identical for either direction 'of rotation, and also thateither member can be the driver. One advantage of using the device withthe members designated as they are in the above description is that thedriven member 9 which carries the manual reset member is stationary inthe released condition as shown in Fig. 3, while the driving membercould continue to rotate, thus facilitating the resetting operapin 2|thus releasing the end 23 of the trigger n tion.

awhile InhavezFillustratedsafidedeseribedxirparifticularaembodiments..of.".my";invention;; modificattonsz thereof vvill occurato'zthose;.Skil18d;in\ the nt. Icdesireit be understood; therefore, that L-mYIHVBIItiOIIiSJIOiJ torbe limited to the particular 55 rearangements:disclosed, and Lintendin; th raprpendediclaimsu to covert; allmodifications which nibmotidepart i romxthe' spirit/and,-scopeiotmyinmention. '1 L v 'iwhatiI rlaimiuasinew andndesireicuttersBatentofitheUnited:States; s:

1.5:A Z:driVing -.zmechanisml.innluding :tdriven rmember havingladrivenielement formed ass'ia -z=smp, zazdriving membenuanaareu'aterspring :hav-

secure biy i110 king ends eircumferentially. spacediapartanduarn15.fentially:spaced aparaoone 'ofgsaid :springuends mangledin'lfrictional tengagement w-itn-saidi driving member: .for::providing'lar driving connection beitween-risaidimembers ethronghmsaidspring oneof rsaid spring endsbeing: arran'ged for engagementbeingiarranged; inw'lengagementxwith saidflrinen *rmember: stop, meansincluding .1 a ;trigger .azpivliotalivmounted onisaid drivenmemberandrhaving -a'1portion' for: engaging the :other ofvsaid ispringiiwitha saidadriveni mernb err stop: means including.-nndsraltdrivingsmember'havingasurface adapted -aitriggertmounted onsaiddriven member-for engaging the other of said spring ends, and means12misaididrivingsme'mber for actuatingsaidtrigger above az red'eterminedtorque to bias said 'arcuate lto iretainisaid spring under compressioniin' iiricfitlonaliengagementtherewith:foriproviding aid'r-iv- 'ngconnection between said driving andiiriven members; means mounted onsaid driving memiSprin'giends t ward ch th r wherebyassaidiar- 5,2berffori-actuatingsaid trigger-to bias "said spring :euate" spring is:compressed out-1 of 'friction'al "enl ga'gement awithassaidirdrivingismember 'releasing maid-driving connection. '1

:52. A :driving mechanism-ninclu'ding ;a driven rendiengaged by -saidtrigger toward: said spirng -enden'gaged bysaid s'topzvvhereby:saidispringi is compressed o'ut of a frictional engagement with s'a'iddrivin'glmember surface releasing: said drivime'mberwhavingr a driven;element: formed:.la :.:1a mgc n ctio dq t hingmmeans on ai driveim'eniberi ior 1 biasing sai'd r trigger out of engage- 11 went W-i-thisaid actuating means and ion-Hatchmctionai eng'agement with saiddrivingmember -s' face.

v '11 6. A='lidriving me'chanismx' including a Tdriv en member having 1a driven element formed 1 as a 'istop; a d-riving member; an 'arcuatespring hav- 'ringfiendsricircumferentiallyr spaced apart andarfisaiidtispring'zends.towardsreach 0ther',:1and.-means-range'd:in"irictiona1 engagement with .said drivrmr said driving memberfor. actuatingsaid biasing :means .rabove -a :apredete'rmining;;;transmitted itnrquextol compress said. spring rout of vfrictionalfen'gagement with said driving member and toz reiieasersaidzdriving:connection. .v I

3,245: driving v mechanism including, a driven rmembei' having adriverielementiormed as a stop, -iamarcuatm-sprin'g;havingsendsicircumferentiall-y ifspaicedrapara one of. saidtspringends:being;;.ar-

- ing member for I. providing a driving connection between said drivingand r' driven rmembeis rth'rough said springp-one ofsaid;springends'beringarranged for engagement withe -said driven member:stop, means including aitrigger zon zsaid "driven member for 1 engagingthe other ofsaid springe'nds; means on saidv driving :membernzfor'lactuating said trigger to bias'saidiarcuate spring rends 'towa'rds'each other whereby: said .iarcuate Ranged rimengagement .with-;saiddrivenimem-ber r spring is: compressedtout ofirictional engagementrstnp, meanszincluding a,trigger-,.pivot'a11y mounted on said drivenmember and having avsportion adapted to: engage the otherof.said;spring-, ends, a tdriving; member having avsuriace: adapted'tozreiwvith s'aid second; driving-member releasing *s'azidcdriving:comiectiomsaid frictional engagemen'tfof i said -drivingmembertandspring being arranged'to i eause slippage ithere'ofrnabovezi apredetermined AJiinfisaid spring under compression ;in: frictiona1:.55atransmitted torquegme'a-nsion :said drivenrmemsrengagementistherewithi011; providing :a :i'dr-iving @connection -between said drivingandzdriven memabe'rs; and means mounted on; said drivingmemfon'actuating .said' trigger. to bias-said spring \lbef fon'zlatchingsaidcarcuateispring in: disengaged "tposition -out of frictional:engagement witirssaid i driving memberaandxmeans: including arese'tidevice o'n saidkdriven member: fonmanually: biasing end-enga edby said H tri er vtowardzgsaid sprin M30 said latchingfmeans :tolreieasedrposition whereby l driving mechanisms including? a driven Hmemb'erihaving' iai .drivenmelement :formed:;.as:=a rstop;.ian arcuatespring;havingiendsmircumieremally spacedapart,v oneof ssaidn'spring:endssbeingeiarranged :in engagement @withcesaidndriveii -said' arcuatespringizis';reengaged" withrsaid; drivizing member to:reestablishthezzdriving. connection ib'etween :said ;2 driving and 1driven :wmembers .ethroughzsaidarcuatespring.

. 17;;A- driving :mechanism including .1: a :.:driven rimember anarcuate.;spring;having ends circumzfzferentially .spacedrapart;onenofrsaid spring-ends being arranged in engagement withnsaidzdriven:Lmember, meansiricluding azdrivingmember with i memberrzstop, meansincluding a-strigge'rz;piv- 'mz'a surfaceadaptedto.iret'ain ,said=spring under btallymounted on' sai'd drivemmembenand-v havaiportion.adapted to" engagezthadtherfof'said springz 'ends; a: drivingmemberc havingraasuriace indented-to retain said'springrrmderilcompressinn mrmemnarengagementitnerewitmiorfipmvidingmwtionafiengagement witlisaid:drivingimember a=- bompressioni'infrictionalengagement-:therewith, r

I -means on"; said":driven member for :.biasing said 'sarcuatesspringends" towards :each other? whereby arcuatet :springl:isi'compressed out;of Effici; ng said": spring :in compressed position. I outtof hers.

.:.:-. 8'. A driving mechanism including 39; .dr-iven member having I avdriven element formed. as; ,a

ston-an arcuate spring having ends circumferentially spaced apart withdriving means thereon, 51 one of said spring end drivingmeansbeingiarranged in engagement-with said driven member stop, meansincluding a trigger pivotally mounted on, said driven, member. havingaportion. for-:en- .gaging the other of said spring end driving means,aqdriving member having a surface adapted to retain said spring undercompression in frictional .engagement therewith, means mounted'on saiddriving member for actuating saidtriggerto bias zsaid spring end engagedby said trigger toward (125 said spring end engaged bysaid stop wherebysaid spring is compressedv out of frictional':en-

gagement with said driving member surface,

, means including a, latching finger pivotally ;mounted on said drivenmember. adapted tobe; 3

-said trigger outof engagement with said actuating means and forlatching said spring;in.-com-,

pressed position out of frictional. engagement with said driving membersurface, and means including a reset device on said driven member forbiasing said latching finger outwardly whereby said trigger is releasedtherefrom'permittingre- 40 1 engagement of said arcuate spring with saiddriving' member surface.

9. A driving mechanism including a; driven member having a drivenelementformedasia stop, an arcuate spring having ends circumferentiallyspaced apart with driving means thereon, one of said spring end driving.means .beingarranged in engagement with said driven member .;stop, meansincluding a trigger pivotallyxmounted ii on said driven member andhaving a. portion go; I adapted to engage the other ofsaid springjenddriving means, a driving member having a surface adapted to retain saidspring under compression in frictional engagement therewith, meansmounted on said driving member foractuating' said trigger tobias saidspring end engaged ;by

1 said trigger toward said spring end, engaged; by -;said stop wherebysaid spring is compressed;out

.of frictional engagementwith said driving member surface, latchingmeans on said drivenmem- 50': -'.ber' for biasing said triggerout ofengagementv with said actuating means and for latching said :spring incompressed position out of frictional engagement with said driving-member--surface,

r 10. A driving mechanism including a :driven .member having a drivenelement .Iformedxas an .adjustable stop, an arcuate spring; havingendspircumferentially spaced apart with driving means thereon, one" of saidspring? end driving means being arranged adj acentlsaid driven mem--mourited on. said: drivenmember and having a portion for'eiigagmg theother of said springend adriving means, a driving member having asurfaceuadapted to retain said spring under com- :DIBSSiOn in frictionalengagement therewith, -means mounted on said driving member foractutating saidstriggermtolcompress said spring out-of frictionalengagement with said driving'member surface whereby said frictionaldriving connection released, meansincluding a latching finger-pivotallymounted on said driven-member adapted to be pivoted outwardly by'outwardmovement of said trigger and having an *angularly arrangedcam surfacewith a-stop at the end thereof for biasing said trigger out ofengagement with said actuating means and for latching said spring incompressedposition out of frictional engagement with said driving membersurface, and means on said driven member for releasing said trigger fromsaid latchingv finger permitting reengagement. of said arcuate springwith said driving member surface. I

11. A driving mechanism including a driven member having a drivenelement formed as an adjustable stop, an arcuate'spring having endscircumferentially spaced apart with driving means thereon, one of saidspring end driving means being arranged adjacent and in engage- -mentwith said drivenmember stop; means 'in- .cluding. a trigger pivotallymounted on said driven member having a portion for engagingthe other aof said spring end driving means, a driving mem- .xber.having a drumportion with a surface adapted :to'retain said spring under compressionin frictional engagement therewith, means rotatably mounted on saiddriving member for actuating saidtrigger to. compress said spring. .outof;.frictional engagement with said driving member surface'wherebysaidfrictional driving connection is released, latching means on saiddriven member for biasing said trigger out of engagement with saidactuating .means and for latching said spring in 'compressed positionout of frictional engagement -with saidu driving member drum surface,.and means including a resilient spring. biased: reset device pivotallymountedon said driven member for normally biasing. said latching fingerinwardly and for: 1 manually biasing said latching. finger outwardlyIw-hereby said trigger is released from said "cam stop permittingreengagement .of said l arcuate spring with said driving member .drumsurfacc. 1 12. A driving mechanism including a driven Y member havingadriven element formed as a stop mounting securing said driven elementtowsaid driven member, an arcuate spring. havingends circumferentially'spaced apart, one of said spring lends. being--arranged in engagementwith said driven inember stop,,means including a trig erpivotallyimounted'on said drivenmember foreng'agin'g theother of saidspring ends and having a; groove therein arranged in engagement withsaid stop tongue member, means including adrivmg member with a surfaceadapted 'to retain said springlunder compression in frictional drivingengagement therewithfor providing a .driving .;con- --nection betweensaid driving and driven members .nthrough said. spring and,permittinggslippage therebetween: above a predetermined torque,means'on said driving :member for actuating. said trigger mto bias .saidarcuate spring ends towards each other zbypturning said. stop throughsaid :tongue and: groove engagement whereby; said her. stop; means 7:including atrigger:rpivotallwuxarcuatespringis;compressedout offrictionalenwith a tongue thereon and having a pivotalammva '9 1gagement -with 'said-"diiiiing memberreleasing-the tfie =end itherecffer biasing said trigger outwardly flictionai driving connection*between-said mem--- intt') engagement with said cam stop and 'out ofblars abbvmsaid predetermined tcrque causing engagement -witmsaidactuating roller whereby slippage in said frictidnat enga-gement; meanson' said spring is latched in compressed position out said-' d'tivemmember -fo'r=-1atch in-g said' triggertm 51 of frictional engagementwith said driving mem hbldfisaid arcr-iate spningnifr compressed dis n Iber di' um surface, andmeans including a'resiligaged posi-tidm routIofifrictional en'gagement with cut-spring biased reset device pivotallymounted" saidildrivingsmemben; andmeans on saidfidrivenr on saiddrivenmember fer-normallybiasing said member "fen; releasing-saidtrigger: permittingzre latching finger inwardly and for manually biasingengagementrofisaidrarcuate spring witii'said driva NM said latchingfingeroutwardly whereby said trig ingnnembez :torreestabfismthedriving-"connection ger 'ismeleased frcm 'said cam'stop permitting rebetweenasaidrdrivi ngsand-dnivensmembers:througlfengagement Of saida'rcuatespring with said driv said arcuate spring. m g member drumsurface.

' 1311A drivingemechanismainclu'dingzra driven A driving: mechanismincluding 'a' driven: members-having: a-:.drivenw element-stormed assaz1 5 memberh'aving a driven element formed asa stop;stomaa;pivotairimountingssecuringgzsaid envenelem a==piv0taI mountingsecuring saiddrive element fo mcntttoza'said: dr'iven member;saididrivei eiement': said dr'ivemmember," d I dr n le "h vin ha-zingraslDtitlfel'ein forzseeuringa saidlfdrivem elea i a""s16t therein fcrsecuring said drive element memqi dimerem vo itinsrrelativ it y 1 drivedifferent positions'rel'ative to said driven membermcmbemwherebzyztheposiiicmofisaidistopxmay her 24;; whereby the positi6n of said step maybe changed? changed; aniancuatezspringahavingr endsncircumaan arcuatespring: having ends*circumferentialiw feizentda-ilyzr spacedi apartwithh driving/r means-'2 spaced apart W h' driving means thereon; ne ofthereon"; one ofisaid: springrendt'drivingi'meanss said spring enddriving means being arranged beingrarranged :in :engagementewithnsaidzdrivena engagement withsaid "driven'member stop', m'ea1'1smemberrstopnmeans inchid-ingra.ztriggempivotally r 231: including atrigger pivotally' mounted on said mounted r011! said: @driven"memberrhawingi aapmas' dr'ii en member having a 'porti'on fcr engaging:the-' tmn-rforr. engagings the: other-t: ofsaidns'pringrendc h r fsaidpring' nd driving m ns, a drivi dniving means,a;dwrvingyzmembenrhavingzavdrumn member havi-ng a surface adapted toretainsaid pontionwitn a -surfacecadaptedvtmaretaim saidn sprin un r mpn fri ion l en e spring; undemcompressicn:inrwfrictionahengaget-e s. wt-therew h; means including a rollrrotatmerit. therewith rmeansinchidingsa I'Ofleniuvotataa abl'jr 'mountedon saidfdriving member foractl'rbly mountedvon said driving membenifontactu-ate atIngsaid tri gi110 p e Said Spring inggsaid triggen-rtonbiasssaiduspringsendnengagedfritidnarengagemenf with S d driving ember byaesaid trigger towardsaidspring-end engaged I s1'1rfa'ce;--means including'a'latchingfinger'pivot'-'-' bw'said step whereby said-ispringnis ficompnessedcall'y'mount'ed onsaid drivenmember adapted'tcontmofivfrictionalr;engagementiwit-h-fsaidsdmivinge be pivotedoutwardlyb'y outward'movement cf", memb e1; 1" drum: surface releasing;thee fridtionali said-5 trigger by said" roller actuating means anddrivingconnection ,ilatchingqmeanscnsaidflmzenr having an angularlyanged cam surface witha" memberifonibiasingesaidritriggerr outofrrengagee Step at" the end *tli'ereof for biasing said" tri mentz-withsaid-.lactuatingrollerz and vfonrlatchingc 4m out of engagement with"said actuating roller: saiddspring int-compressed position out creme?wherebys d'spring 'isIatched-"in compressed 'D tionaiwv engagementwithns'aid driving!v member: sition'nut'bf fricticnafengagem'entwith'sai'd'driv dmim-rsunfaceg- .andrrmeans'i includingf'avres-ilienti'1 1% member surface; and'means inc u r spmng-gbiasedi reset;rdevicewpivgtgflsr'gmounted jflnli d'eviceuomsa'id iiii ivingmemb'er'fcrmanually-biassaid; driven imemberrfor:normally-biasing:'saidii'45;. 'S'1 fi fi r G Y-W bY'said'fi latching-finger? inwardly and rfbrrmanually,vbiasarigger is Y released permitting "reengagement om? ingrsaidulatchingefingerroutwardiy whereby saidc Said? 'fl e Sp g" W thisaid driving smemben triggen-iislreleased :from said camsstoppermitting: surface:"-..

reen aeementnois. said iarcuateespring 'rwitns sa'id l6. .Aedriinn ni m"n' l inefi a driven a m memberflrumfsumcey member having'ardrr'venelement formed'as ai'stopnl 14: Aadrivingg mechanismincluding; anrarcuatexspringrhaving :en'dsecircumferential'lyr member1-. having aidrivenneienrent rformedaswan ed p' r ine f i spring'"ends'-being ar-"- adinstablewstom an arcuaterspringshaving ends'irangedfor engagement with saiddri'ven'l member: circumferentiallyspae'edi'. apant driving"? p; 'c nsificlu n "a"tr er'pivotally'mountediimeans; thereqn; 011 f -sai pm end;;drivii1'g:=- 555 onzsai'd :driven:membernfor engaging: thefotkier dfif mang gbeingyarranged adjacent-andin engage-2 said 'sprihgendaimeans includingia"driving memr mentwitmsaidtdrivenr memberrstop, means iIiL-Z ber'adaptedito retairrsaidspringinfricticnaltene cluding atrigger pivotaliy mounted on saiddri'venzz g m fi rewitfifdr providinga driving con mfimbenanduhavingajportidn for ren'gagingethes nection betweensai'd' fdriving and:drivenmembersn OthGInOfi said: spring endiiriving means; a' 'driving rthrcu lifsa d= spr means cn'said-driving meme member. rhavingeardmmportionizwithz a; surface ber fdr actuating-maid ctriggen to biassaid'arcu'aten adapted torretainsaid:springmndenrccmpressione spriendsrtowards eachanther-wher y" innfrictional {engagement therewith ameans: arcuate springfis compressed:out of frictional-1 ens. cludinra-irollerrrotatably mounted'nn! saidcdri. gement' with; saidrzvzlriiing" member releasingrr ing member for actuatingcsaid'tri'gger:tobiasasaidd ;said-1drivingr conn d frictional en' c nr nd-.: eagedabwsa'rdirtrigger'tcward said ment ofisaididrum andzspring being-arrangedtog spring; endvenga'gedzbmsaidg.stopawherebysaidra cause s1ippa e-.:thereofabove-a predetermine'di: sm'inggishcompressedouts-10ffrictional-engage! rque, means including: .ai'latchingfinger1=piV0t'+-i--' ment withrsaid driving member drum surfaceneg allymo n d'i n idriv r' r l h n leasingsaidufrictionaidrivinggconnectiom'zm-eansa:v 7o said-.'arcuate spring-fin: disengaged: posit-ion out. oftjincludin aqlatchingtnngem iyetanyrmountedrbnn fr l a em n h sa d: dr nmb r: 1

""saidadrinensmemb.emandradaptedrt0-be pivotedand-meanscincludingaaresilientlybiased reset dee outwardly'bmmutwarmmovement of: saidctriggervice onvsaid idriven memberforrnormally {biasing-1' b'yqsaidr-rollen actuating meansgsaidfingemiaving saidelatchingifinger inwardly: to iatchedzpesitibnzramangylarbqarrangedrcamr surfaccwithza stomat; g ct -said arcuatezspringimdisengaged'pcsition: wands 11 for -manually biasing said latchingfinger ,11 wardly wherebysaid arcuate spring is reenergized with saiddriving member to'reestablish the driving connection between saiddriving and-driven members throughsaid arcuate spring.

. '17. A driving mechanism including a driven member having a drivenelement formedas a stop,,

a pivotal mounting securing said drive element to said driven member,said driven element having a slottherein for securing said drive elementin different positionsrelative to said driven member forchanging'theposition of-said stop,.an arcuate spring having ends circumferentiallyspaced apart; with driving means thereon, onevof said spring end drivingmeans being arranged adjacent .and in engagement with said driven memberstop, means including a trigger pivotally mountedon said drivenmember-having a portion for engaging the other of said spring enddriving means, a

driving member having a'suriace adapted to re-v tain said spring undercompression in frictional,

engagement therewith, means including aroller rotatably mounted on saiddriving member for actuating said trigger to compress said springout of-frictional engagement with said-driving member'surface whereby saidfrictional driving-0on nection is released, means including'a latchingfinger pivotally'mountedon said driven'member adapted to be pivotedoutwardly by-outward movement of said trigger by said roller actuatingmeans and having an angularly arranged cam ate spring with said :drivingmember surface.

18. A driving mechanism includinga driven member having a drivenelement'formed' as a stop with a tongue thereon, a pivotal'mountingsecuring'said drive element to-said drive mem-, ber, an arcuate springhaving ends circumferen-a tially spaced apart,'one of said springrendsbeing arranged in engagement with said driveni member stop,meansincludinga trigger pivotally" mounted on said drive member forengaging the other ofsaid spring ends and having a groove:

therein arranged in engagement-with said stop tongue member, meansincluding a driving 'mem'#'" ber with a surface adapted to retain saidspring in frictional engagement under compression therewith forproviding a driving connection between said drivemembers through saidspring and-"permitting slippage therebetweni above a predeterminedtorque, means on said driving member for actuating said trigger to' biassaid arcuate'spring ends towards each other by 'turning'said stopthrough said tongue and groove engagement whereby said arcuatespring'is' compressed out of frictional engagementwith said drivingmember drum surface releasingthe frictional driving connection betweensaid drive members above said predetermined torque caus ing slippage insaid frictional engagement, means including a latching finger pivotallymounted 'on said driven member'adapted to be pivoted out-" 'wardly byoutward movement of said trigger by said actuating meansand havinganangularly' arranged cam surface for biasing and trigger outwardly out;of engagement-with "said actuating means andxfor latching said arcuatespringin compressed disengaged position out of frictional" engagementwith said second drivemember, and means onsaid driven member fornormally biasing said latching finger inwardly to assist latchingsaid-arcuate spring in disengaged po sitionand for manually biasing saidlatching finger-outwardly for releasing said trigger wheree by' saidarcuate spring is reengaged with said driving member to reestablish thedriving icon-F nection'between said drive members through said arcuatespring. *1,

:119'. A driving mechanism including a drive member having-a drivenelement formed as :a' stop. with a'tongue-thereon; a pivotal mountingsecuring said drive element tosa'id driven mem-i' ber,;an arcuate springhaving ends circumferen tially spaced apart, oneofrsaid sprin'gendsbe'-'r ing arranged adjacent and in engagement with" said driven memberstop, means including" a trig-"- ger pivotally mounted -.on said drivenmember" and having a portion'for engaging the other of saidspring endsand a groove therein arranged" in engagement with'said stoptongue'membery means including a driving memberhaving a drum portionwith av surface adapted to retain said springunder compression infrictional eng'a'gement' therewith for providing a driving connectionbetween said' driving and" driven members' through saidspringand'permittin'g slip-j page" therebetween above a predeterminedtorque,'-means on said driving member for ac? tu'ating said triggertobias said arcuate spring endvengaged by said trigger toward saidspring end engaged by said stop and turning said stopthrough' saidtongue and groove engagement whereby the'end'of said arcuate. springengaged by said stop'is moved in the opposite direction compressing saidarcuate spring out of frictional" engagement with said driving memberdrum sur-f face and releasing thefrictional driving connec tion:betweensaiddr'iving and driven membersabove said predetermined torque causingslipping insaid frictional engagement of said drum and spring, meansincluding a latching finger pivotally mounted on said drivenmemberadapted to be pivoted outwardly byoutward movement of said trigger bysaid trigger actuating means and having an angularlyc arranged camsurface for biasing said trigger outwardly out of engagement with saidactuating means and for'latch ing said arcuate spring in compresseddisen gaged position out of frictional engagement with arcuate spring indisengaged position and for manually biasing said latching fingeroutwardly for' releasing said trigger therefrom whereby said arcuatespring is reengaged'with said driving member drum'surface to'reestablishthe driving connection between said driving and driven mem bers throughsaid arcuate spring.

20. A driving mechanism including a driven member formed as a plate andhaving a driven element formed as a stop, a pivotal mounting 'se' curingsaid drive element to said driven mem-l -.ber, said driven elementhaving a slot therein with means for securing said drive elementindifierent positions relative to said driven member whereby theposition of said stop is changed, an arcuate spring having ends circumfer'entially spaced apart with driving means there'ong-oneof ber havinga drum portion with a surface adapted to retain said spring undercompression in frictional engagement therewith for providing a drivingconnection between said driving and driven members through said spring,means including a roller rotatably mounted on said driving member foractuating said trigger to bias said arcuate spring end engaged by saidtrigger toward said spring end engaged by said stop whereby said arcuatespring is compressed out of frictional engagement with said drivingmember drum surface releasing said driving connection, said frictionalengagement of said drum and spring being arranged to cause slippagethereof above a predetermined torque, means including a latching fingerpivotally mounted on said driven member adapted to be pivoted outwardlyby outward movement of said trigger by said roller actuating means andhaving an angularly arranged cam surface with a stop at the end thereoffor biasing said trigger outwardly into engagement with said cam stopand out of engagement with said actuating roller and for latching saidarcuate spring in compressed disengaged position out on said drivenmember for normally biasing said latching finger inwardlyto assist inlatching said arcuate spring in disengaged position and for manuallybiasing said latching finger outwardly whereby said trigger is releasedpermitting reengagement of said arcuate spring with said driving memberdrum surface to reestablishthe driving connection between said drivingand drivenmembers through said arcuate spring.

21. A driving mechanism including a driven member formed as a plate andhaving a driven element formed as a stop with a tongue thereon, apivotal mounting securing said driven element to said driven member, anarcuate spring having ends circumferentially spaced apart with drivingmeans thereon, one of said spring end driving means being arrangedadjacent and in engagement with said driven member stop, means includinga trigger pivotally mounted on said driven member having a portion forengaging the other of said spring end driving means and having a groovetherein arranged in engagement with said stop tongue member, meansincluding a driving member having a drum portion with a surface adaptedto retain said spring under compression in frictional engagementtherewith for providing a driving connection between said driving anddriven members through said spring and permitting slippage therebetweenabove a predetermined transmitted torque, means including a rollerrotatably mounted on said driving member for actuating said trigger tobias said arcuate spring end engaged by said trigger toward said springend engaged by said stop and turning said stop through said tongue andgroove engagement whereby the end of said arcuate spring engaged by saidstop is moved in the opposite direction compressing said arcuate springout of frictional engagement with said driving member drum surface andreleasing the frictional driving connection between said driving anddriven members above said predetermined torque causing slippage in saidfrictional engagement of said drum and spring, means including alatching finger pivotally mounted on said driven member adapted to bepivoted outwardly by outward movement of said trigger by said rolieractuating means and having an angularly arranged cam surface with a stopat the end thereof for biasing said trigger outwardly into engagementwith said cam stop and out of engagement with said actuating roller andfor latching said arcuate spring in compressed disengaged position outof frictional engagement with said driving member drum surface, andmeans including a resilient coil spring biased reset device pivotallymounted on said driven member for normally biasing said latching fingerinwardly to assist in latching said arcuate spring. in disengagedposition and for manually biasing said latching finger outwardly wherebysaid trigger is released permitting reengagement of said arcuate springwith said driving member drum suriace to reestablish the drivingconnection between said driving and driven members through said arcuatespring.

22. A driving mechanism including a driven member, a driving member, anarcuate spring having ends circumferentially spaced apart and arrangedin frictional engagement with said driving member for providing adriving connection between said members through said spring, one of saidspring ends being arranged for engagement with said driven member, meanson said driven member for compressing said arcuate spring out offrictional engagement with said driving member whereby said drivingconnection is released above a predetermined torque and automaticre-establishmeht of said connection is prevented, and means on saiddriven member for manually releasing said arcuate spring to re-establishsaid frictional driving connection.

23. A driving mechanism including a driven member having a drivenelement formed as a stop, an arcuate spring having endscircumferentially spaced apart, one of said spring ends being arrangedin engagement with said driven a member stop, means including a triggeron said. driven member for engaging the other of said spring ends, adriving member adapted to retain said spring in frictional engagementtherewith for providing a driving connection between said driving anddriven members, and means on said driving member for actuating saidtrigger above a predetermined torque to bias said spring ends towardseach other whereby said spring is compressed out of frictionalengagement with said driving member releasing said driving connection.

HUGH M. STEPHENSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 775,063 Dexter Nov. 15, 19041,677,961 Fay July 24, 1928 2,012,418 Burke Aug. 27, 1935 FOREIGNPATENTS Number Country Date 4,785 Great Britain Feb. 23, 1897

